More sliders, more success for Logan

The recent injuries to Mariano Rivera and David Robertson have caused something of a stir at the back end of the Yankees bullpen. Rafael Soriano, once the nominal “seventh-inning guy,” has taken hold of the closer’s role, meaning that the Yankees have needed to piece together their setup duties.

Fortunately for New York, they have gotten big contributions from relievers Cory Wade and Boone Logan, who have combined to allow eight runs and strike out 44 hitters over their 32.2 innings this year and are “climbing the ladder,” so to speak. Wade is interesting in his own right, but let’s focus on Logan for right now.

So far this season, Logan is striking out batters in 35 percent of their plate appearances against him, placing him ninth among big league relievers and well above his career norms in that category. The reasonable next question is: what’s up? How has Boone Logan become so good? The answer, it appears, has mostly to do with his low-80s slider, his breaking pitch of choice. First, observe his pitch frequencies since he came to the Yankees in 2010:

Sliders have been on the increase for Logan, and this year, he’s actually thrown more of them than four and two-seam fastballs combined. And that looks like it’s a good thing: Logan’s slider has been his best pitch, by far.

whiff% is whiffs per swing; called% is called strikes per pitch; ball% is balls per pitch

Anything over ~40 percent whiffs per swing is a good strikeout pitch, and Logan has taken it to the next level this season. His slider is also thrown for a ball less than the average slider is, and he can drop it in for a called strike early in the count if he wants to. The combination of throwing more sliders and getting more whiffs when he throws them is the driving force behind Logan’s success this year.